An ideal permanent ventricular assist system (VAS) or total artificial heart (TAH) will not include tubes or wires passing through the skin. This proposal describes development of a telemetry system capable of providing the bi-directional communications between implanted and external components required for safe operation. The ECG signal is a naturally occurring form of telemetry. The voltages sensed by the ECG machine are the result of minute electrical currents generated by the heart flowing through the resistances of the tissues in the thorax. In similar fashion, the Conductance Telemetry System (CTS) transmitter admits minute high frequency currents into tissues via one pair of electrodes producing voltages that can be detected by a remote receiver connected to a second pair of external electrodes. A telemetry system based on this principle will be highly resistant to interruptions of service if issues pertaining to its reliance on chronic skin electrodes can be adequately addressed. The goals of this program are to: 1) develop custom electronic components that make it easy to integrate the CTS into a host system; 2) develop skin electrode systems suitable for use in VAS and TAH patients, and, 3) obtain third party certification of compliance with safety standards. PROPOSED COMMERCIAL APPLICATION: Both the NHLBI and private industry are supporting the devleopment of implantable blood pumps to address the needs of an estimated 30-40,000 patients annually who might benefit from permanent mechanical circulatory support. The proposed device is applicable to virtually all of these systems.